Although the Asian American population has grown dramatically in size and diversity in recent decades, there are wide gaps in our knowledge of health and healthcare for this population. Asian subgroups (Asian Indian, Chinese, Filipino, Japanese, Korean, and Vietnamese) are often aggregated in clinical and population-based studies because of small numbers in any one subgroup. In particular, data are lacking on Type 2 diabetes and obesity for Asian Americans, suggested to have increased risk of Type 2 diabetes. Moreover, no data explains whether this applies equally for all Asian American subgroups. The prevalence of obesity, pre-diabetes, diabetes and the diabetic complications of diabetes are largely unknown in specific Asian subgroups. There is also a controversy about how obesity should be defined for Asians. In 2004, the World Health Organization recommended lower body mass index (BMI) cut points to define overweight and obesity for people of Asian descent worldwide. However the evidence on which this is based is debatable, and it is possible that this association will be different in Asian subgroups living in the U.S. It is also unknown if risk factors for diabetes are similarly predictive for Asian American subgroups and Non-Hispanic Whites (NHWs). Better information is needed concerning screening, incidence, prevalence, risk factors, natural history of obesity and diabetes, and healthcare and patient factors that affect treatment disparities for Asian American subgroups. This application aims to examine diabetes screening, risk and care both to fill gaps in knowledge of diabetes disparities and to inform clinical decision making regarding screening and healthcare for Asian Americans. We propose to construct a mixed historical and prospective longitudinal cohort by linking existing clinical databases in a large (20,000), multiethnic sample of contemporary Asians in California. We will define Asian subgroups through self-report, and will include a sample of NHWs for comparison. Use of electronic health records in this epidemiologic study will allow highly cost efficient assembly and follow-up of this cohort. The overall goal of this application is to address a substantial gap in existing knowledge regarding diabetes risk in Asian racial/ethnic minorities. This study will provide a greater understanding of diabetes among Asian ethnic minorities in a comparable environment, and would contribute both to a global understanding of risk for Asian populations and to more targeted research, public health and clinical efforts throughout the U.S.